Reciprocating cutting tool

ABSTRACT

The invention relates to a reciprocating cutting tool such as a surgical file system for precisely removing bone and/or other tissue material. The system allows a user to maneuver the system and navigate into hard to access site. The tool may be used to perform a spinal decompression by removing tissue that impinges a spinal nerve.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/932,690, filed Oct. 31, 2007, now U.S. Pat. No. 8,080,011, which is acontinuation of U.S. patent application Ser. No. 10/675,068, filed Sep.29, 2003, now U.S. Pat. No. 7,390,330, which claims the benefit of U.S.Provisional Application No. 60/414,690, filed Sep. 27, 2002, entitledSHIELDED RECIPROCATING SURGICAL FILE. The entirety of each of thepriority applications is hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to systems and methods for cuttingmaterial, and can relate particularly to a reciprocating surgical filesystem for cutting, removing, grinding, shaping and sculpturing boneand/or tissue material.

2. Description of the Related Art

Adjacent spinal vertebrae are spaced by intervertebral discs that aretough and semi-elastic. The discs act as a flexible spacer between thevertebrae that makeup the backbone. Vertebrae are shaped to provide abony tubular shaped tunnel between upper and lower pairs of vertebraeand this tunnel is made-up in part by the spacing disc. These tubularshaped tunnels are called neuroforamen and serve as a passageway fornerve roots. The size of the neuroforamen tubular shaped tunnels is aclose fit for the nerve roots that pass through these tunnels on theirway from the spinal cord to the arms, legs and other muscles.

Each year millions of people encounter neck and back injuries. Manymillion suffer from truly problematic back pain that either keeps themout of work or debilitates them in some way. Many vertebral and discinjuries result in pain from nerve irritation and compression.

When an intervertebral disc is damaged, often it is because of aphysical overrotation between two vertebrae and normal wear and tear.When a vertebra is overrotated, small facet joints called thezygapophyseal capsules that are located to the left and right sides ofthe disc are damaged. When the body incurs damage to these small joints,unwanted osteophytes and bony overgrowths frequently occur at the edgesof these tiny joints. The unwanted bony overgrowth restricts theneuroforamen and pinches the delicate and sensitive nerve roots.

Also, with age, for many people, the sensation of thirst is somewhatreduced. As a result, sometimes less water is consumed than needed bythe body. The intervertebral discs depend on water as well as othermaterials to maintain a healthy function. When a disc loses a part ofits fluid mass it is said to desiccate. When a disc is desiccated itreduces in height and reduces the space between the two vertebras it isconnected to, that is, the neuroforamen becomes constricted and pinchesnerve roots.

Pinched nerves that are constrained in between vertebras can cause neckand back pain. The bony overgrowth and a reduction in the space betweenvertebras pinch the nerves causing irritation, pain and numbness. Thepinching can potentially result in a loss of use of the limbs controlledby the affected nerve.

Thus, when intervertebral discs are damaged from accident, age and/orgeneral wear and tear the intervertebral nerve roots in the neuroforamenare irritated and pinched and can cause unwanted involuntary muscularcontractions. The muscle contractions can come in the form of acontinuous low-grade ache or become more severe as a spasm. The musclecontractions can act to further compress the space between thevertebras, which further pinches the nerve. This becomes a severelypainful, self-destructive and self-feeding problem.

One current technology to treat a patient with nerve compression thatcauses pain and numbness involves the removal of the disc and fusion ofthe vertebra below with the vertebra above it. Vertebral fusion removesa disc that was flexible and fuses one vertebra together with theadjacent vertebra resulting in a rigid joint between two vertebrae. Thiscauses added strain on the disc above and below the now rigid bonefusion. Sometimes the attempted fusion of one vertebra onto anothervertebra is unsuccessful and does not provide the intended fusion.

Disadvantageously, the intervertebral fusion is an invasive andrelatively complicated procedure. In addition, and undesirably, thefusion process can result in a long hospital stay for the patient, along recuperation and rehabilitation period and high costs for both thepatient and care providers.

SUMMARY

Embodiments of the invention overcome some or all of the abovedisadvantages by providing systems and methods for tissue cutting andremoval including a reciprocating surgical file. Some embodimentsprovide surgical instrumentation that allows a surgeon to navigate intothe tiny neuroforamen next to delicate nerves and locate and removeobstructions of tissue that can cause nerve compression and irritation.Advantageously, this offers many patients a minimally invasive surgicaloption that can result in shorter hospital stays and lower cost.

Embodiments of the invention can desirably be adapted and tailored toserve at least three surgical fields. These include, but are not limitedto, neurosurgery, orthopaedic surgery and plastic surgery. Theneurosurgical embodiments enable surgeons to safely enlarge theconstricted neuroforamen and provide more space for the nerve roots topass through the rigid bony vertebral structure, thereby relieving thenerve pinching and compression.

The orthopaedic embodiments provide improved bone and/or tissue removalinstrumentation and methodology, for example, for orthopaedic surgicalprocedures such as knee surgery. The plastic surgery embodiments provideimproved bone and/or tissue sculpturing instrumentation and methodology,for example, for cosmetic surgical procedures such as nose reshaping orrhinoplasty. Other embodiments can be used as non-medical cutting tools.

Some embodiments include a surgical instrument comprising a blade; ahousing in which the blade moves, the housing having a long axis; atransmission that converts rotary motion to reciprocating, linearmotion, wherein the transmission is coupled to the blade such that theblade moves reciprocally in the housing; a first opening in the housingthrough which a portion of the blade is exposed; and a cutting surfaceon the exposed portion of the blade, the surface configured to performat least one of grinding, filing, and cutting of tissue.

In some embodiments the housing is concave about at least a portion ofits long axis, such as at least a distal portion of its long axis. Insome embodiments the housing is convex about at least a portion of itslong axis, such as at least a distal portion of its long axis. In someembodiments the first opening is in an opening surface on the housing.In some embodiments the housing is curved along its long axis, to assistin placing the surgical instrument in the body of a patient. In someembodiments the blade is substantially flat.

In some embodiments the housing is curved along its long axis in adirection toward the opening surface. Some embodiments further compriseat least one bearing retainer for reducing friction. In some embodimentsthe at least one bearing retainer has at least one slot configured totransmit fluid toward a distal end of the instrument. Some embodimentsfurther comprise at least one fiberoptic in or on the housing, fortransmission of at least one of a video signal and illumination light.In some embodiments the housing has at least a second opening at adistal end of the housing.

Some embodiments further comprise at least two lenses coupled to the atleast one fiberoptic. In some embodiments, at least one of the at leasttwo lenses is disposed at a distal end of the housing, and another ofthe at least two lenses is disposed in proximity to the first opening inthe housing. Some embodiments further comprise a pump for pumping fluidthrough the surgical instrument. In some embodiments the pump ismechanically coupled to the transmission. In some embodiments, thetransmission comprises: two surfaces that are a substantially fixeddistance apart; a cam that rotates about a central axis, the centralaxis being at an angle to a plane extending between the two surfaces;and the cam having a curvilinear body, the body having a nonuniformthickness, wherein the body continuously contacts the two surfaces asthe cam rotates about the central axis, such that the two surfacesremain at the substantially fixed distance apart as they move linearlyin response to the cam's rotation about the central axis.

In some embodiments, the cam's central axis is substantially parallel toa direction of the linear motion of the two surfaces. In someembodiments, the central axis is substantially perpendicular to theplane extending between the two surfaces. In some embodiments the twosurfaces move linearly back and forth in reciprocating motion inresponse to the cam's rotation about the central axis. In someembodiments the curvilinear body has a shape comprising at least twotoruses, the at least two toruses being partially superimposed, and eachof the at least two toruses has a central axis, wherein the central axesof the at least two toruses are at an angle to each other. In someembodiments at least one bearing comprises the two surfaces. In someembodiments two bearings respectively comprise the two surfaces.

In some embodiments the curvilinear body is disposed at an angle to thecentral axis of the cam. Some embodiments include an apparatus fortranslating a rotary motion to a linear motion, the apparatuscomprising: two surfaces that are a substantially fixed distance apart;and a cam that rotates about a central axis, the central axis being atan angle to a plane extending between the two surfaces; the cam having acurvilinear body, the body having a nonuniform thickness, wherein thebody continuously contacts the two surfaces as the cam rotates about thecentral axis, such that the two surfaces remain at the substantiallyfixed distance apart as they move linearly in response to the cam'srotation about the central axis.

In some embodiments the cam's central axis is substantially parallel toa direction of the linear motion of the two surfaces. In someembodiments the central axis is substantially perpendicular to the planeextending between the two surfaces. In some embodiments the two surfacesmove linearly back and forth in reciprocating motion in response to thecam's rotation about the central axis. In some embodiments thecurvilinear body has a shape comprising at least two toruses, the atleast two toruses being partially superimposed, and each of the at leasttwo toruses has a central axis, wherein the central axes of the at leasttwo toruses are at an angle to each other.

In some embodiments at least one bearing comprises the two surfaces. Insome embodiments two bearings respectively comprise the two surfaces. Insome embodiments the curvilinear body is disposed at an angle to thecentral axis of the cam. Some embodiments include a pump comprising: afluid path; two plungers configured to at least partially occlude thefluid path; a cam configured to cause the two plungers to at leastpartially occlude the fluid path alternatingly; and at least one checkvalve along the fluid path for reducing backflow of fluid within thefluid path.

In some embodiments the cam translates in a direction that issubstantially perpendicular to a long axis of at least one of the twoplungers. In some embodiments the cam translates in a direction that issubstantially perpendicular to a long axis of each of the two plungers.In some embodiments the pump comprises: a fluid path; two plungersconfigured to at least partially occlude the fluid path; a camconfigured to cause the two plungers to at least partially occlude thefluid path alternatingly; and at least one check valve along the fluidpath for reducing backflow of fluid within the fluid path.

In some embodiments the cam translates in a direction that issubstantially perpendicular to a long axis of at least one of the twoplungers. In some embodiments the cam translates in a direction that issubstantially perpendicular to a long axis of each of the two plungers.Some embodiments of the instrument further comprise at least one openingin the exposed portion of the blade, for transmitting fluid. In someembodiments the cutting surface comprises an abrasive material. In someembodiments the cutting surfaces comprises diamond. In some embodimentsthe blade comprises stainless steel.

Some embodiments further comprise a handpiece coupled to the housing.Some embodiments further comprise a video camera. In some embodimentsthe camera is configured to couple with a fiberoptic that extends to adistal end of the housing. In some embodiments a video camera is locatedin the handpiece. Some embodiments further comprise a watertight seal inthe handpiece. In some embodiments the handpiece is configured tocontain the video camera in a chamber such that the watertight sealreduces or prevents ingress of at least one of water and bacteria fromoutside the handpiece into the chamber containing the video camera inthe handpiece.

Some embodiments further comprise a motor in the handpiece, the motorconfigured to power the rotary motion. In some embodiments the motorcomprises a gas turbine. Some embodiments further comprise a cordconfigured to couple to a proximal end of the surgical instrument, thecord comprising at least one of a fiberoptic, an electrical line, anirrigation channel, a suction line, and a gas tube for powering a gasturbine motor in the surgical instrument.

For purposes of summarizing the invention, certain aspects, advantagesand novel features of the invention have been described herein above. Ofcourse, it is to be understood that not necessarily all such advantagesmay be achieved in accordance with any particular embodiment of theinvention. Thus, the invention may be embodied or carried out in amanner that achieves or optimizes one advantage or group of advantagesas taught or suggested herein without necessarily achieving otheradvantages as may be taught or suggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments of the inventionwill become readily apparent to those skilled in the art from thefollowing detailed description of the preferred embodiments havingreference to the attached figures, the invention not being limited toany particular preferred embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus summarized the general nature of the invention and some ofits features and advantages, certain preferred embodiments andmodifications thereof will become apparent to those skilled in the artfrom the detailed description herein having reference to the figuresthat follow, of which:

FIG. 1 is a simplified schematic view of a surgical file systemillustrating features and advantages in accordance with an embodiment ofthe invention.

FIG. 2 is a simplified perspective view of the surgical file system ofFIG. 1.

FIG. 3 is a simplified perspective view of a surgical file device with acurved distal tip configuration illustrating features and advantages inaccordance with an embodiment of the invention.

FIG. 4 is a simplified perspective view of a surgical file device with astraight distal tip configuration illustrating features and advantagesin accordance with another embodiment of the invention.

FIG. 5 is a simplified side view of a surgical file device illustratingfeatures and advantages in accordance with an embodiment of theinvention.

FIG. 6 is a simplified partially exploded view of the surgical filedevice of FIG. 5.

FIG. 7 is a simplified perspective view of the surgical file device ofFIG. 5 with the distal cover removed illustrating features andadvantages in accordance with an embodiment of the invention.

FIG. 8 is a simplified perspective view of a distal tip assembly of thesurgical file device of FIG. 5.

FIG. 9 is a simplified exploded perspective view of the distal tipassembly of FIG. 8 illustrating features and advantages in accordancewith an embodiment of the invention.

FIG. 10 is a sectional view along line 10-10 of FIG. 5 illustratingfeatures and advantages in accordance with an embodiment of theinvention.

FIG. 11 is a sectional view along line 11-11 of FIG. 5 illustratingfeatures and advantages in accordance with an embodiment of theinvention.

FIG. 12 is a simplified perspective view of a surgical cutting bladeillustrating features and advantages in accordance with an embodiment ofthe invention.

FIG. 13 is a simplified schematic cross-section view of a convexsurgical file cutting surface illustrating features and advantages inaccordance with an embodiment of the invention.

FIG. 14 is a simplified schematic cross-section view of a concavesurgical file cutting surface illustrating features and advantages inaccordance with another embodiment of the invention.

FIG. 15 is a simplified schematic side view sectional view of surgicalfile distal tip with a top cutting surface illustrating features andadvantages in accordance with an embodiment of the invention.

FIG. 16 is a simplified schematic side sectional view of a surgical filedistal tip with a top cutting surface illustrating features andadvantages in accordance with another embodiment of the invention.

FIG. 17 is a simplified perspective view of a surgical file cuttingsurface with abrasives illustrating features and advantages inaccordance with an embodiment of the invention.

FIG. 18 is a simplified perspective view of a surgical file cuttingsurface with irrigation fluid openings illustrating features andadvantages in accordance with an embodiment of the invention.

FIG. 19 is a simplified schematic view of a surgical file cutting bladewith irrigation fluid flow therethrough illustrating features andadvantages in accordance with an embodiment of the invention.

FIG. 20 is a simplified schematic cross-section view of a surgical filedistal cutting tip with irrigation fluid passageways illustratingfeatures and advantages in accordance with an embodiment of theinvention.

FIG. 21 is a simplified side sectional view of a surgical file distalcutting tip with a linear reciprocation stroke illustrating features andadvantages in accordance with an embodiment of the invention.

FIG. 22 is a simplified side sectional view of a surgical file distalcutting tip with fiber optic probes illustrating features and advantagesin accordance with an embodiment of the invention.

FIG. 23 is a simplified sectional view along line 23-23 of FIG. 22illustrating features and advantages in accordance with an embodiment ofthe invention.

FIG. 24 is a simplified side sectional view of a surgical file distalcutting tip with an illumination and vision system illustrating featuresand advantages in accordance with an embodiment of the invention.

FIG. 25 is a simplified schematic view of an arrangement of lenses of asurgical file illumination and vision system illustrating features andadvantages in accordance with an embodiment of the invention.

FIG. 26 is a simplified schematic view of display images provided by asurgical file illumination and vision system illustrating features andadvantages in accordance with an embodiment of the invention.

FIG. 27 is a simplified perspective view of a dual torus and drive shaftillustrating features and advantages in accordance with an embodiment ofthe invention.

FIG. 28 is a simplified side view of the dual torus and drive shaft ofFIG. 27.

FIG. 29 is a simplified schematic view of a dual torus partialsuperposition illustrating features and advantages in accordance with anembodiment of the invention.

FIG. 30 is a simplified schematic graphical representation of variationin outer rim thickness of a dual torus or toroid illustrating featuresand advantages in accordance with an embodiment of the invention.

FIG. 31A is a simplified sectional view along line 31-31 of FIG. 28illustrating features and advantages in accordance with an embodiment ofthe invention.

FIG. 31B is a simplified sectional view along line 31-31 of FIG. 28illustrating features and advantages in accordance with anotherembodiment of the invention.

FIG. 31C is a simplified sectional view along line 31-31 of FIG. 28illustrating features and advantages in accordance with yet anotherembodiment of the invention.

FIG. 32 is a simplified perspective view of a distal cutting blade and areciprocating slide plate that connects to the blade illustratingfeatures and advantages in accordance with an embodiment of theinvention.

FIG. 33 is a simplified schematic side view of a distal cutting bladeconnected to a slide blade illustrating features and advantages inaccordance with an embodiment of the invention.

FIG. 34 is a simplified schematic view of toroid drive and associatedbearings illustrating features and advantages in accordance with anembodiment of the invention.

FIG. 35 is a simplified schematic view of toroid drive and associatedbearings illustrating features and advantages in accordance with anotherembodiment of the invention.

FIG. 36 is a simplified perspective view of a surgical file transmissionsystem in a test set-up illustrating features and advantages inaccordance with an embodiment of the invention.

FIG. 37 is a simplified side cross-sectional view of a surgical filepulsatile pump system illustrating features and advantages in accordancewith an embodiment of the invention.

FIG. 38 is a simplified side cross-sectional view of a surgical filepulsatile pump system illustrating features and advantages in accordancewith another embodiment of the invention.

FIG. 39 is a simplified exploded perspective view of a surgical filepowered handpiece illustrating features and advantages in accordancewith another embodiment of the invention.

FIG. 40A is a simplified sectional view along line 40-40 of FIG. 39illustrating features and advantages in accordance with an embodiment ofthe invention.

FIG. 40B is a simplified sectional view along line 40-40 of FIG. 39illustrating features and advantages in accordance with anotherembodiment of the invention.

FIG. 40C is a simplified sectional view along line 40-40 of FIG. 39illustrating features and advantages in accordance with yet anotherembodiment of the invention.

FIG. 41 is a simplified schematic view of a bone and/or tissue removalprocedure illustrating features and advantages in accordance with anembodiment of the invention.

FIG. 42 is a simplified perspective view of a bone and/or tissue removalprocedure on a plastic anatomical model of the human spine illustratingfeatures and advantages in accordance with an embodiment of theinvention.

FIG. 43 simplified side view of a orthopaedic surgical file instrumentillustrating features and advantages in accordance with an embodiment ofthe invention.

FIG. 44 is a simplified front view of a distal cutting assembly of thesurgical file instrument of FIG. 43.

FIG. 45 is a simplified bottom view of the distal cutting assembly ofFIG. 44.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the invention described herein relategenerally to systems and methods for tissue cutting and removal and, inparticular, to a shielded reciprocating surgical file system forcutting, removing, shaping and sculpturing bone and/or tissue materialunder direct vision.

While the description sets forth various embodiment specific details, itwill be appreciated that the description is illustrative only and shouldnot be construed in any way as limiting the invention. Furthermore,various applications of the invention, and modifications thereto, whichmay occur to those who are skilled in the art, are also encompassed bythe general concepts described herein.

FIGS. 1 and 2 show a surgical file system 10 generally comprising amotorized reciprocating shielded surgical file instrument, apparatus,assembly or device 12 and a mobile portable control system 14 connectedvia a flexible umbilical cable 16. The surgical file device 12 generallycomprises a distal tip assembly 18 and a powered handpiece 20.Reciprocating as used herein generally includes back and forth motionand to and from motion.

The system 14 generally comprises a mobile portable stand, cabinet ortrolley 22 that supports a controller or control unit or box 24 and acomputer system 26. In on embodiment, the system 14 has a footprint ofabout 0.2 m² (2 square feet (ft²)) and a height of about 1.8 m (6 feet(ft)). In modified embodiments, other suitable dimensions may beefficaciously used, as needed or desired. The system 14 may also utilizewireless communication.

The cabinet 22 has a plurality of drawers or compartments 28 to storesystem parts, including spare parts, such as cables, connection lines,powered hand piece 20 and an array of various disposable distal cuttingtip assemblies, for example, for neurosurgery, orthopaedic surgery andplastic surgery. The storage drawers 28 also serve to storeinstructions.

The cabinet 22 has a plurality of wheels 30 such as caster wheels toenable movement of the system 14. In the illustrated embodiment, thecabinet 22 has four wheels 30. The caster wheels 30 have wheel locks orother suitable fastening mechanisms to enable stationarily locking theunit at the desired position in the operating room or other area.

The computer system 26 comprises a central processing unit (CPU) 32, amonitor 34, a keyboard 36 including a mouse and a color printer toproduce color pictures. The CPU 32 may be supported on (see, forexample, FIG. 1) or within (see, for example, FIG. 2) the movablecabinet 22. The CPU 32 includes a video processing system, such as butnot limited to a data acquisition board and the like, to process videosignals from the surgical file device 12 and supply the signals to themonitor or video display 34. The CPU 32 has a printer port to interfaceit with the color printer.

The display monitor 34 can comprise any one of a number of suitablecommercially available monitors. In one embodiment, the display 34 is a17-inch (43 cm) liquid crystal display (LCD) monitor.

The storage cabinet 22 includes a substantially vertical pole or rod 38to support the monitor 34. The height and tilt angle of the display 34is adjustable to allow suitable viewing for the operating surgeons. Inone embodiment, the monitor 34 is positioned at a height of about 1.5meters (5 feet). As discussed further below, the monitor 34 can displaya magnified visual picture of the view from the distal end of thecutting tip assembly 18.

The cabinet 22 includes one or more hooks or supports 42 for mounting ofan irrigation fluid bag, container or pouch 44. The hooks 42 can bepositioned at a suitable position, for example, on the pole 38. Theirrigation bag 44 is provided sterile irrigation water from a source 46through a feedline 48. The sterile water is transported to the distalcutting tip assembly 18 during device operation through feed line 50.

In one embodiment, sterile water is provided to the distal cutting tipassembly 18 through the control unit 24 via feedline 50 a. In a modifiedembodiment, the sterile water is provided directly to the distal cuttingtip assembly 18 via feedline 50 b.

The control unit 24 is supported at a suitable working height by thecabinet structure 22. The control unit 24 is operatively interfaced orconnected the cable 16 at its proximal end 40. In the illustratedembodiment, the cable 16 connects to a front face 52 of the control box24. The control box 24 and the CPU 32 can be housed in a single unit.

The control unit 24 and the computer system 26 are powered by aconventional 115-Volt AC electrical power supply 54, for example, byconnecting a male plug to a wall receptacle. In modified embodiments,the system may be powered by a portable power supply such as a generatorand the like.

In one embodiment, the control unit 24 connects to a pressurized gas orair source supply 56 via feedline 58. As discussed further below, thepressurized gas is used to power an air turbine motor of the poweredhandpiece 20. The pressurized gas is supplied by the hospital or housesupply. In modified embodiments, a portable pressurized gas source sucha cylinder may be efficaciously used, as needed or desired.

In one embodiment, the pressurized gas and the irrigation water aresupplied from the control unit 24 and through the umbilical cable 16 tothe surgical file device 12. In addition, the cable 16 provides videosignals from the surgical file device 12 to the control unit 24 andcomputer system 26. The umbilical cable 16 provides a mechanical andwaterproof connection for electrical, video, pressurized gas andirrigation water supply. In modified embodiments, one or more of theelectrical and video signals, gas and water may be transmitted throughseparate cables with efficacy, as needed or desired.

The cable 16 can be any suitable length, for example, about 16 feetlong. The cable 16 is sterilizable. The cable 16 may also be used toprovide a suction line, as needed or desired.

The control box 24 houses switches and valves to control the flow of thepressurized gas and irrigation water. The control unit 24 has electricalcontrols for the handpiece 20 and video signals for the computer system26. The control unit 24 may also include sensors such as pressuresensors, flow rate sensors and the like to monitor the flow of thepressurized gas and irrigation water.

Software is provided that interfaces with the control unit 24 to monitorand control system operation and perform various other relatedfunctions. For example, the software allows the operating room personnelto enter the patient identification and date and other pertinent datainto the computer for record reference.

The software also allows operating room personnel to change videopicture zoom ratios and to control and modify details of the picture forclarity. The computer based system enables the operating personnel tosave pictures of the patient's anatomy, including before and afterpictures, to a computer file and to print out color pictures in seconds.

The software is used to control the pressurized gas and irrigationliquid flow to the surgical file device 12. The software can also beused to turn the device 12 on and off and control the frequency ofcutting blade reciprocation during filing procedures.

The control unit 24 accommodates connection to existing cauterizingequipment. As discussed further below, and as shown in phantom in FIG.1, the control unit 24 can be connected to a cauterizing system 60through connection line 61 to stop or prevent undesirable bleedingduring surgery.

In brief, to enable the surgeon to stop the bleeding of freshly cut bonetissue, the cutting blade surface can feature an electrically conductivesurface that is operatively connected to an electric circuit, forexample, 60. This allows a controlled pulse of electricity to generate asmall amount of heat applied directly onto the bone surface to coagulatethe blood and stop the bleeding at the freshly cut bone surface only,while insulating delicate nerve roots from unwanted heat damage. Theirrigation water also works in conjunction to assist in keeping heatprecisely localized and preventing heat injury to the nearby delicatenerve roots and spinal cord.

FIG. 3 shows the surgical file device 12 with a distal tip assembly 18having a generally curved and/or angled configuration. FIG. 4 shows thesurgical file device 12 with a distal tip assembly 18′ having agenerally straight configuration. The powered handpiece 20 has at itsproximal end 62 a quick connect docking feature 64 to enable connectionto the umbilical cable 16 that provides a mechanical and waterproofconnection for electrical, pressurized gas and irrigation water supply.

FIG. 5 shows the surgical file device 12 connected to the umbilicalcable 16 at its distal end 66. The interface or connection between aproximal end 330 of the powered handpiece 18 and the cable 16 includes acover or housing 68. In the illustrated embodiment, the cover 68 isgenerally frusto-conical in shape, though in modified embodiments othersuitable shapes such as cylindrical and the like may be efficaciouslyutilized, as needed or desired.

The distal tip assembly 18 at its proximal portion or end 70 includes acover or housing 72. In the illustrated embodiment, the cover 72 isgenerally frusto-conical in shape, though in modified embodiments othersuitable shapes such as cylindrical and the like may be efficaciouslyutilized, as needed or desired.

The powered handpiece 20 includes a cover 74 intermediate the front andback covers 68 and 72. In the illustrated embodiment, the cover 74 isgenerally cylindrical in shape and can include a longitudinallyextending bulging portion 76 for housing a video camera. In otherembodiments, the cover 74 may be efficaciously contoured in suitableergonomic shapes that facilitate operation by a surgeon or otheroperator.

The covers 68, 72, 74 can be formed from a number of suitably durablematerials. In one embodiment, the covers 68, 72, 74 are formed from asuitable plastic such as a thermoplastic. In another embodiment, thecovers 68, 72, 74 are formed from a suitable metal such as stainlesssteel. In modified embodiments, other suitable plastics, metals, alloys,ceramics, combinations thereof, among others, may be efficaciouslyutilized, as needed or desired. Suitable surface coatings or finishesmay be applied, as required or desired.

The covers 68, 72, 74 can be fabricated by using a number ofmanufacturing techniques. These include, but are not limited to,molding, machining, casting, forging, laser cutting and/or processing,laminating, adhesively fixing, welding, combinations thereof, amongothers, with efficacy, as needed or desired.

FIG. 6 shows a partially exploded view of the surgical file device 12.As discussed further below, the powered handpiece 20 includes a videocamera 78 and a micro-motor 80 that provides rotary motion which isconverted to linear reciprocating motion within the distal tip assembly18. FIG. 7 shows another perspective view of the surgical file device 12with the distal cover 72 removed illustrating some of the features ofthe distal tip assembly.

Distal Tip Assembly

FIGS. 8 and 9 show the distal tip assembly 18 in greater detail. In oneembodiment, the composite tip 18 has a length of about 10 cm (4 inches)to about 15 cm (6 inches), including all values and sub-rangestherebetween. In one embodiment, the composite tip 18 has a length ofabout 5 cm (2 inches) to about 30 cm (12 inches), including all valuesand sub-ranges therebetween. In modified embodiments, other suitablelengths may be efficaciously utilized, as needed or desired.

The distal tip assembly 18 is sterile to maintain appropriate surgicalstandards and is provided in a sterile packaging. In one embodiment, thedistal tip assembly 18 is for one time use and is disposable thereafter.As described further below, embodiments of the distal tip assembly 18include a cartilage or other tissue and bone removal file with vision,illumination, irrigation and cauterization features.

The distal tip assembly 18 generally comprises a distal tip portion 92that has a distal-most end 94 and a proximal portion extending into thecover 72 that encloses a housing 96 that receives a toroidal powerconverter system 98 and a water pump system. The distal tip assembly 18further includes an interface member 102 and a coupling 104 thatfacilitate connection between the distal tip assembly 18 and the poweredhandpiece 20.

The distal tip portion 92 generally comprises a reciprocating cutting orfiling blade 106 that is enclosed in a protective case or shield 108.The shield 108 has an aperture, window, opening 112 to expose a cuttingsurface 114 of the filing blade 106 proximate the distal end 94.Desirably, the shielded blade 106 permits surgical bone and/or tissueremoval substantially without risk of damage to nearby delicate tissuessuch as nerve tissue.

The distal tip portion 92 can be configured to be small and thin so itis minimally intrusive and can go around corners and into any smallinaccessible blind channels where nerves are located. The distal tipportion 92 can be configured to fit any desired cavity or contouredshape. The tip portion 92 can be supplied in a variety of sizes andshapes to suit a particular application such as, but not limited to,neurosurgery, orthopaedic surgery and plastic surgery.

The blade cutting surface 114 can be located on the end of an extensionwith a bend 116 of any desired angle. In the illustrated embodiment ofFIGS. 8 and 9, the tip portion 92 has a curved, angled or bentconfiguration with the bend 116. In another embodiment, the distal tipportion 92 has a substantially straight and/or planar (flat)configuration.

The tip portion 92 further includes a linear bearing retainer 118 withinthe shield 108. The reciprocating blade 106 is precision fitted withinthe bearing retainer 118 that allows free linear motion of thereciprocation blade stroke. Advantageously, the bearing retainer 118provides low friction bearing surfaces for the reciprocating motion ofthe blade 106.

The bearing retainer 118 comprises a plurality of stationary linearbearings 120 which are positioned on the top, bottom and both sides ofthe reciprocation blade. The top linear bearing 120 has an aperture,opening or window 122 that is substantially aligned with the shieldaperture 112 to expose the blade cutting surface 114. In one embodiment,the tip portion 92 (and hence the lengths of the blade cutting surface114 and the apertures 112, 122) are configured so that substantially theentire blade cutting surface 114 is exposed during the full bladereciprocation cycle.

The bearing retainer 118 can be formed from a number of suitably durablematerials. In one embodiment, the bearing retainer 118 is formed from asuitable plastic such as a thermoplastic. In modified embodiments, othersuitable plastics, metals, alloys, ceramics, combinations thereof, amongothers, may be efficaciously utilized, as needed or desired. Suitablesurface coatings or finishes may be applied, as required or desired.

The bearing retainer 118 can be fabricated by using a number ofmanufacturing techniques. These include, but are not limited to,molding, machining, casting, forging, laser cutting and/or processing,laminating, adhesively fixing, welding, combinations thereof, amongothers, with efficacy, as needed or desired.

As described in more detail below, the distal tip portion 92 furtherincludes a pair of fiber optic probes 124, 126 that are part of anon-board optical illumination and vision system. The fiber optic probes124, 126 optically connect or interface at their proximal ends to thevideo camera 78.

The bottom or lower fiber optic probe 124 is below the lower bearing120. The fiber optic probe 124 may be housed within the shield 108 or itmay have its independent protective jacket below the shield 108. Thefiber optic probe 124 has a distal end 128 at about the distal-most end94 of the tip portion 92.

The top or lower fiber optic probe 126 is above the upper bearing 120.The fiber optic probe 126 may be housed within the shield 108 or it mayhave its independent protective jacket above the shield 108. The fiberoptic probe 126 has a distal end 130 proximal to a proximal end 132 ofthe aperture 112 and/or the cutting surface 114.

The shield 108 can include the aperture 112 on any one of its sidesdepending on the positioning of the cutting surface 114. This includesthe top (as shown in, for example, FIGS. 8 and 9), the bottom and thesides of the shield 108 and even its distal end 134. The shield 108 hasa longitudinally extending cavity that houses the blade 106, the bearingretainer 118 and in some embodiments the fiber optic probes 124, 126. Inthe illustrated embodiment, the distal end 134 closes the longitudinalshield cavity.

In one embodiment, the shield 108 is capable of deflecting and bends atpredetermined and/or low loads (for example about 2 lbs.) in order toprevent injury or damage to tissue, such as nerve tissue, engaged by theshield 108. The shield 108 has a predetermined stress-strain curve andspring constant to provide the desired deflection and can comprise, forexample, a suitable polymer and the like. The shield 108 may bend at thebend location 116 or at a location proximate to the contact with thetissue. One or more of the associated tip portion 92 components such asthe blade 106, bearings 120 and the fiber optic probes 124, 126 can alsobend with the shield 108, as needed or desired.

The shield 108 can be formed from a number of suitably durablematerials. In one embodiment, the shield 108 is formed from a suitableplastic such as a thermoplastic. In another embodiment, the shield 108is formed from a polymer that is flexible or can bend under apredetermined load. In modified embodiments, other suitable plastics,metals, alloys, ceramics, combinations thereof, among others, may beefficaciously utilized, as needed or desired. Suitable surface coatingsor finishes may be applied, as required or desired.

The shield 108 can be fabricated by using a number of manufacturingtechniques. These include, but are not limited to, molding, machining,casting, forging, laser cutting and/or processing, laminating,adhesively fixing, welding, combinations thereof, among others, withefficacy, as needed or desired.

The shield 108, the bearing retainer 118 and the fiber optic probes 124,126 generally conform in shape to the longitudinal profile of the blade106. In the illustrated embodiment of FIGS. 8 and 9, this is a curved,angled or bent profile with a bend at around 116.

FIG. 10 shows a cross-sectional view of the distal tip portion 92 at alocation proximal to the aperture 112 and the bend 116. The blade 106 issubstantially centrally located within the shield or outer jacket 108.The blade 106 is precision fitted within the bearing retainer 118including the linear bearings 120. The respective lower and upper fiberoptic probes 124, 126 are buffered from the blade 106 by the stationarybearings 120.

The cutting blade linear bearing 120 has a series of shallow slots 190running substantially longitudinally in line with the proximal to distalaxis. The slots 190 serve as water passageways to enable irrigationwater to be transported from a proximal to a distal location. Theirrigation water serves several functions and provides severaladvantages.

The water is a lubricant for the interface between the moving blade 106and the stationary linear bearings 120, which in one embodiment arepositioned on the top and bottom and both sides of the reciprocationblade 106. The water cools the blade and bearing material, and in theembodiment the bearing material is plastic, prevents the plastic bearingmaterial from getting hot and softening. The water also serves to wetthe cutting blade surface. The water is also used to clean tissue andtransport the cut tissue away from the cutting blade 106. Additionally,water transported across the linear blade 106 intimately irrigates thevolume of water in the distal blade area to clear the optical visionfield for clear viewing.

FIG. 11 shows a cross-sectional view of the distal tip portion 92 at theshield aperture 112. The cutting surface 114 of the blade 106 is exposedand is above the lower bearing 120, the lower fiber optic probe 124 anda lower portion 192 of the shield 108. The drawing also shows portionsof the shield 108 and the upper bearing 120 at the tip distal end 94. Inthis embodiment, the cross-sectional profile of the cutting surface 114is convex and the associated portions of the shield 108, bearings 120and lower fiber optic probe 124 generally conform to this shape.

In one embodiment, and as described further below, the toroidal drivesystem 98 is substantially mounted within the housing 96 and generallycomprises a rotatable toroid drive 136 and a drive slide 138. A driveshaft 140 is connected to the handpiece motor 80 and transfers rotarymotion to the toroid drive 136 which engages the linear slider 138 toconvert rotary motion into reciprocating motion that is provided to theblade 106 for performing bone and/or tissue removal operations. Inmodified embodiments, other suitable rotary to reciprocating motionmechanisms or devices may be used, as needed or desired, toreciprocatingly drive the blade 106.

As discussed further below, the drive shaft 140 is connected to thetoroid drive 136 and has a specially designed female receptor hole. Thereceptor hole allows the drive shaft 140 to substantially irrotationallymate with a power drive shaft of the motor 80.

The housing 96 has a distal end 142 and a proximal end 144 and agenerally flat recessed surface 146 extending from the distal end 142towards the proximal end 144. The linear slide 138 is reciprocatinglyseated on or within the recessed surface 146. The housing 96 includes acavity 148 intermediate the recessed surface 146 and the housingproximal end 144 that receives the rotatable toroid drive 136. Thehousing proximal end 144 has an opening 149 that receives a power shaftof the handpiece motor 80 that connects to the drive shaft 140.

The housing 96 can be formed from a number of suitably durablematerials. In one embodiment, the housing 96 is formed from a suitableplastic such as a thermoplastic. In modified embodiments, other suitableplastics, metals, alloys, ceramics, combinations thereof, among others,may be efficaciously utilized, as needed or desired. Suitable surfacecoatings or finishes may be applied, as required or desired.

The housing 96 can be fabricated by using a number of manufacturingtechniques. These include, but are not limited to, molding, machining,casting, forging, laser cutting and/or processing, laminating,adhesively fixing, welding, combinations thereof, among others, withefficacy, as needed or desired. The housing 96 and bearing retainer 118may comprise an integral unit, for example, they may be formed bymolding and the like.

The toroid drive 136 is connected with the drive shaft 140. The toroiddrive 136 has an outer rim 150 that is engaged with the slider 138 andtransmits rotary motion that is converted into reciprocating motion bythe slider 138.

The slide plate 138 has a distal end 152, a proximal end 154 and aspecially contoured slot 156 proximate to the proximal end 152 with apair of generally opposed bearing surfaces 164, 166. As described ingreater detail below, the slot 156 receives the rotating outer rim 150of the toroid drive 136.

The blade 106 is connected to the slide 138. As described in greaterdetail below, this connection utilizes shear pins to provide a safetymechanism against blade buckling.

The slide 138 can be formed from a number of suitably durable materials.In one embodiment, the slide 138 is formed from a suitable plastic suchas a thermoplastic. In modified embodiments, other suitable plastics,metals, alloys, ceramics, combinations thereof, among others, may beefficaciously utilized, as needed or desired. Suitable surface coatingsor finishes may be applied, as required or desired.

The slide 138 can be fabricated by using a number of manufacturingtechniques. These include, but are not limited to, molding, machining,casting, forging, laser cutting and/or processing, laminating,adhesively fixing, welding, combinations thereof, among others, withefficacy, as needed or desired.

The interface member 102 has an opening 158 which allows passage of thefiber optic probes 124, 126 for connection to the camera 78. Theinterface member 102 has an opening 160 that receives that receives apower shaft of the handpiece motor 80 that connects to the drive shaft140.

The coupling 104 has an opening 162 that receives that receives a powershaft of the handpiece motor 80 that connects to the drive shaft 140.The openings 149, 160 and 162 are substantially aligned with oneanother.

The interface member 102 and coupling 104 can be formed from a number ofsuitably durable materials. In one embodiment, the interface member 102and coupling 104 are formed from a suitable plastic such as athermoplastic. In modified embodiments, other suitable plastics, metals,alloys, ceramics, combinations thereof, among others, may beefficaciously utilized, as needed or desired. Suitable surface coatingsor finishes may be applied, as required or desired.

The interface member 102 and coupling 104 can be fabricated by using anumber of manufacturing techniques. These include, but are not limitedto, molding, machining, casting, forging, laser cutting and/orprocessing, laminating, adhesively fixing, welding, combinationsthereof, among others, with efficacy, as needed or desired.

BLADE EMBODIMENTS

Embodiments of the invention provide reciprocating cutting blade forprecision bone and/or tissue removal. In one embodiment, thereciprocating cutting blade is shielded or covered or guarded on fivesides to provide a shielded surgical file.

The shielded file can be flat, planar, convex or concave in itscross-section. The shielded file can extend generally straight or becurved, angled or bent along its longitudinal axis. Advantageously, theangled configuration allows the cutting surface to travel around acorner to reach into usually inaccessible body cavities. Desirably, thisprovides the ability to remove unwanted tissue in a blind tunnel or bodycavity while enabling direct vision through the illumination and visionprobes.

The shielded file can be dimensioned in a number of manners. Theshielded file can be any length or width suitable for the human ormammalian anatomy proportions. For other non-medical applications, theshielded file can be of any length or width to suit the material removalapplication.

The thickness of the shielded file can be varied to be very thin. In oneembodiment, the thickness can be of the order of 1/10^(th) of an inch.Advantageously, this enables the shielded file to fit into small spacessuch as between a nerve and the foramen opening that it is passingthrough. In other embodiments, the thickness of the shielded file can begreater, as needed or desired.

The cutting blade can be shaped and contoured in several configurations.In one embodiment, the reciprocating cutting blade is straight andplaner (in one flat plane). In another embodiment. the reciprocatingcutting blade that is curved convex or concave in its cross sectionalshape. In yet another embodiment, the reciprocating cutting blade thatis substantially straight in its longitudinal axis. In still anotherembodiment, the reciprocating cutting blade is curved in itslongitudinal axis.

The thickness of the cutting blade drive 106 can be varied. In oneembodiment, the cutting blade thickness is in the range from about 100microns or μm (0.004 inches) to about 300 μm (0.012 inches). In anotherembodiment, the cutting blade thickness is in the range from about 50 μm(0.002 inches) to about 600 μm (0.024 inches). In yet anotherembodiment, the cutting blade thickness is in the range from about 25 gm(0.001 inches) to about 2.5 mm (0.1 inches). In modified embodiments,other suitable dimensions may be efficaciously utilized, as needed ordesired.

The cutting blade 106 can be formed from a number of suitably durablematerials. In one embodiment, the cutting blade 106 is formed fromsteel. In another embodiment, the cutting blade 106 comprises springstainless steel. In modified embodiments, other suitable metals, alloys,plastics, ceramics, combinations thereof, among others, may beefficaciously utilized, as needed or desired. Suitable surface coatingsor finishes may be applied, as required or desired.

The cutting blade 106 can be fabricated by using a number ofmanufacturing techniques. These include, but are not limited to,molding, machining, casting, forging, laser cutting and/or processing,laminating, adhesively fixing, welding, combinations thereof, amongothers, with efficacy, as needed or desired.

In one embodiment, the cutting blade 106 is flexible. Advantageously,this allows the cutting blade to be easily bent, angled or curved alongits length as it is enclosed in a bent, angled or curved outer shield108. In another embodiment, the cutting blade is substantially rigid.This can be suitable for blade configurations that are generallystraight. The rigid blade may also be bent by suitable techniques, asneeded or desired. In modified embodiments, the cutting blade 106 mayefficaciously comprise one or more flexible portions and one or morerigid portions, as needed or desired.

FIG. 12 shows an embodiment of the cutting blade 106. The blade 106comprises a thin flexible material that is capable of bending along itslength. The blade 106 includes a distal section or portion 194 with thecutting surface 114, a medial section or portion 196 and a proximalsection or portion 198. When enclosed within the curved, angled or bentshield 108 the blade 106 flexes like a thin spring to conform to theshape of the shield or guide cover 108. Thus, the medial section 196 iscurved, angled or bent while the respective distal and proximal sections194, 198 extend generally straight.

FIG. 13 shows a cross-section of a cutting surface 114 a and anassociated portion 202 a of the shield 108 a having a generally convexconfiguration suited for some particular bone and/or tissue removalapplications. The convex curvature of the cutting surface 114 a can alsobe advantageous in providing enhanced rigidity to the thin cuttingsurface 114 a and/or the associated blade 106.

FIG. 14 shows a cross-section of a cutting surface 114 b and anassociated portion 202 b of the shield 108 b having a generally concaveconfiguration suited for particular bone and/or tissue removalapplications. The concave curvature of the cutting surface 114 b canalso be advantageous in providing enhanced rigidity to the thin cuttingsurface 114 b and/or the associated blade 106.

FIG. 15 shows a lengthwise-section of the distal tip portion 92 having acutting surface 114 c on the top or upper side of the reciprocatingblade 106 within the non-moving shield 108. This configuration is suitedfor some particular bone and/or tissue removal applications. The bend116 allows the cutting surface 114 c to pass into a cavity that involvestraveling around a corner. The direction of blade travel is generallydenoted by arrows 204.

FIG. 16 shows a lengthwise-section of the distal tip portion 92 having acutting surface 114 d on the bottom or lower side of the reciprocatingblade 106 within the non-moving shield 108. This configuration is suitedfor some particular bone and/or tissue removal applications. The bend116 allows the cutting surface 114 d to pass into a cavity that involvestraveling around a corner. The direction of blade travel is generallydenoted by arrows 204.

FIG. 17 shows the cutting surface 114 including an abrasive material orabrasives 206 for cutting, removing, filing or grinding bone and/ortissue materials. For clarity, one side of the shield 108 has beenremoved in the drawing. Any one of a number of suitable abrasives may beused that are safe to use within a patient's body or are biocompatibleand hard. In one embodiment, the abrasives 206 comprise embeddeddiamonds or diamond particles.

Also shown in FIG. 17 is a lateral slot or opening at the tip portiondistal end 94. Advantageously, the distal opening 208 allows the removalof any bone and/or tissue debris that may collect within the distal andprovides for flushing out of the debris as the blade cutting surface 114reciprocates and the irrigation fluid flows out of the instrument.

FIG. 18 shows the blade cutting surface 114 including a plurality ofmicro holes or openings 212 for the flow of irrigation fluidtherethrough. For clarity the abrasives are not shown in the drawing.The holes 212 are in fluid, liquid or hydraulic communication with thelongitudinal slots 190 of the lower linear bearing 120. The slots 190 ofthe upper linear bearing 120 also provide irrigation water to thecutting area.

FIG. 19 schematically depicts the fluid, liquid or hydrauliccommunication between the bearing slot(s) 190 and the cutting surfaceholes 212. The flow of water from the bearing slots(s) 190 and the microhole openings 212 is generally indicated by arrows 214. The water isforced to flow up, down or out through the openings 212 in the cuttingblade surface 114 and away from the blade cutting surface 114. The waterwashes away cut material and keeps debris from clogging the cuttingsurface 114 to maintain optimum cutting and material removalperformance, and to keep the cutting area cool to prevent tissuenecrosis damage.

The water also flows over the moving (reciprocating) cutting blade 106and drive mechanism or bearings 120 to provide cooling and lubrication.The water can be forced into the cutting cavity 112 to flush away microcutting debris and maintain a clear field of view for video navigationand visualization. The water can be forced into the cutting area cavity112 to clean and remove freshly cut bone cells and bone fragments toprevent repopulation and unwanted bone growth in the area.

FIG. 20 is another schematic depiction showing the fluid, liquid orhydraulic communication between the irrigation fluid holes 212 and thebearing irrigation passageways 190. The drawing also shows the abrasivematerial or abrasives 206 of the blade cutting surface 114.

FIG. 21 shows the reciprocation blade stroke direction as generallyindicated by arrows 216. The free linear motion of the reciprocationblade stroke is a linear stroke. In one embodiment, for applicationswithin the human body, the linear stroke is in the range from about 2.5mm (0.1 inches) to about 7.6 mm (0.3 inches), including all values andsub-ranges therebetween. In another embodiment, the linear stroke is inthe range from about 1.3 mm (0.05 inches) to about 12.7 mm (0.5 inches),including all values and sub-ranges therebetween. In yet anotherembodiment, the linear stroke is in the range from about 0.25 mm (0.01inches) to about 25.4 mm (1 inch), including all values and sub-rangestherebetween. In modified embodiments, the linear stroke mayefficaciously be lower or higher depending on the particularapplication, as needed or desired.

Cauterization

In accordance with one embodiment, the surgical file instrument 12 canstop the small amount of bleeding of freshly cut or sculpture shapedbone or other tissue by accommodating connection to existing cauterizingequipment 60. In this embodiment, the special feature the system has isa non-electrically conductive shield 108, which is covering anelectrically conductive metal file blade 106.

When bleeding of the freshly cut bone is detected, the file cuttingblade 106 can be brought back into contact with the freshly shaped bonethat may be bleeding slightly. A pulse of electricity can be momentarilyapplied that will flow from the metal blade file surface into thebleeding bone or other tissue surfaces. This will heat the bleeding boneor other tissue surfaces, coagulate the blood flow and advantageouslystop the bleeding of the bone and/or tissue surface. Desirably, theirrigation flow facilitates localizing the heat and cooling while theshield 108 protects the adjacent nerves and spine from heat.

Illumination and Vision Probes

FIG. 22 shows a fiber optic vision system 218 including the fiber opticprobes 124 and 126. The fiber optic vision system 218, in some surgicalembodiments, enables surgeons to visually see and verify the presence ofunwanted bone and cartilage buildup that is causing nerve rootcompression and damage to normal body functions. This information on theunwanted material can be documented and recorded by saving visualpictures into a computer database and printing color picturesimmediately for reference and record.

The lower fiber optic probe 124 includes a plurality of optical fibers220 a that optically terminates at a distal lens array or arrangement222 a. The lens array 222 a is positioned at substantially the tipdistal end 94. The fiber optic probe 124 may be placed within the shield108 or it may have a separate housing. The lower fiber optic probe 124generally follows the longitudinal profile of the distal tip portion 92,the blade 106 and/or the shield 108.

The upper fiber optic probe 126 includes a plurality of optical fibers220 b that optically terminates at a distal lens array or arrangement222 b. The lens array 222 b is positioned proximal to the blade cuttingsurface 114. The fiber optic probe 126 may be placed within the shield108 or it may have a separate housing. The upper fiber optic probe 126generally follows the longitudinal profile of the distal tip portion 92,the blade 106 and/or the shield 108.

Advantageously, the fiber optic vision system 218 enables visual viewingof the patients body cavities all during insertion and placement of thecutting blade. This is intended to enable the surgeon to safely navigatethe tiny body cavities such as neuro-foramen tubular canal and avoiddamage to fragile nerve roots.

FIG. 23 shows the optical fibers 220 a in more detail. The upper opticalfibers 220 b (220 b′, 220 b″) have a similar configuration andfunctioning though they may have a different curvature or be flat andplanar. The optical fibers 220 a comprise a central plurality of opticalvision fibers 220 a′ flanked by light or illumination fibers 220 a″. Theoptical vision fibers 220 a′ are connected at their proximal end to thevideo camera 78.

The fiber optical illumination fibers 220 a″ illuminate the body cavityand enable video visualization. An LED located at the proximal end ofthe fiber optics illumination fibers 220 a″ is used transmit light tothe distal end of the illumination fibers 220 a″ to provide illuminatinglight. Advantageously, the direct vision optical system 218 enablessurgeons to safely navigate into blind cavities of the human body and toilluminate and see specific body anatomy such as nerves and bonybuildups that could be irritating and pressing against nerves causingnerve compression.

In the illustrated embodiment, the direct vision optical system 218desirably provides an integrated illumination and optical vision system.The optics for vision and illumination are included within the distaltip assembly 18 which in some embodiments is a docking sterile one timeuse assembly.

Referring in particular to FIG. 24, the distal optical system lensesarrangements 222 a and 222 b are each arrayed in three segments. Thelower optical segments 222 a are arranged with a video imaging lens 222a′ centered medially and with illuminating lenses 222 a″ positioned onthe right and left lateral sides. The upper optical segments 222 b arearranged with a video imaging lens 222 b′ centered medially and withilluminating lenses 222 b″ positioned on the right and left lateralsides.

FIG. 25 shows the lens arrays 222 a, 222 b in more detail. The lateralsides of the central lenses 222 a′, 222 b′ have a respective semi-arcmale shape 224 a′, 224 b′ to each of their left and right sides. Theilluminating lenses 222 a″, 222 b″ are shaped to have mating femalesemi-arc medial sides 226 a″, 226 b″ on there medial sides which mateinto the male mating features 224 a′, 224 b′ of the central lens sides.

Advantageously, such mating lens arrays 222 a, 222 b can accommodate awide range of instrument sizes while using substantially the same basiclens assembly design. Different lenses may be used in the design and thecurvature of the lens array adjusted and changed to provide the desiredillumination and/or field of view. For example, for a particular medialvideo imaging lens 222 a′, 222 b′ the curvature of the side illuminatinglenses 222 a″, 222 b″ can be adjusted or changed to illuminate thedesired field of view. This desirably saves on cost since micro lensesare very expensive to tool up and make. The distal tip assembly 18 canhave numerous sizes with varying cross sections of the distal tipportion 92 depending on the particular application and advantageouslysubstantially the same basic lens assembly design 222 a, 222 b can beutilized with the different sizes.

Additionally the mating lenses 222 a′, 222 b′ and 222 a″, 222 b″ allowthe black out of the respective mating surfaces 224 a′, 224 b′ and 226a″ and 226 b″ to substantially prevent illumination light from passinglaterally into the imaging lens 222 a′, 222 b′ and degrading the opticalquality of the resulting picture. A lens set comprising the centralimaging lens 222 a′, 222 b′ and one each right and left illuminatinglenses 222 a″, 222 b″ can be assembled onto a wide range of instrumentdisposable cutting tips 18 in an assembly that has an optical distallens system which is very thin in cross section and that the lensesfollow the instrument cross sectional curve. Advantageously, forembodiments of the invention and in particular the neurosurgeryembodiments, having a very thin cross section enables the instrumentsdistal tip to fit into the tiny space between a nerve root and itsneuroforamen opening.

As shown in FIG. 26 the images from the direct vision optical system 218can be viewed on the LCD monitor 34. The drawing shows an example of thedisplay with a view 228 from the upper fiberoptic 126 looking onto theblade 106 and a view 230 from the lower fiberoptic 124 looking out fromthe instrument distal end 92.

Toroidal Transmission System

The toroidal transmission or power conversion system 98 is a mechanicalconversion device that converts rotary to reciprocating motion oraction. The powered handpiece 20 houses a rotating motor 80 to power thecutting action of the tissue removal instrument or blade 106. Therotating mechanical action of the motor 80 is converted intoreciprocating mechanical motion of a suitable reciprocal stroke length.It is desirable that the mechanical motion conversion device be simpleand have few parts.

Having a video camera system mounted directly into a reciprocatingmotion mechanical device can create a stability problem with respect toinherent vibration that is usually inherent in all reciprocating motionmechanical devices. Advantageously, the toroidal drive system 98 ofembodiments of the invention provides a desirable solution for thevibration problem since it has low or minimum levels of associatedvibration. This advantageously provides a stable platform for thecapture of high quality pictures by the video system including thecamera 78 housed in the handpiece 20.

The toroidal drive system 98 inherently has few parts and can be builtto be very low vibration due to low mass of the reciprocatingcomponents. Thus, the toroidal drive system 98 can provide the poweredhandpiece 20 with a stable platform and a smooth running mechanicalaction. The transmission system of embodiments of the invention hasutility in a number of fields and applications where conversion ofrotary motion to reciprocating motion is desired.

FIGS. 27 and 28 show the toroid drive 136 and the female receptor driveshaft 140. In one embodiment, the toroid drive 136 and the drive shaft140 comprise an integral unit and are formed as a single piece. Inanother embodiment, the toroid drive 136 and the drive shaft 140 can berigidly connected to one another.

The toroid drive 136 and the drive shaft 140 can be formed from a numberof suitably durable materials. In one embodiment, the toroid drive 136and the drive shaft 140 are formed from a suitable plastic by molding.The plastic material may comprise a suitable thermoplastic. In modifiedembodiments, other suitable plastics, metals, alloys, ceramics,combinations thereof, among others, may be efficaciously utilized, asneeded or desired. Suitable surface coatings or finishes may be applied,as required or desired.

The toroid drive 136 and the drive shaft 140 can be fabricated by usinga number of manufacturing techniques. These include, but are not limitedto, molding, machining, casting, forging, laser cutting and/orprocessing, laminating, adhesively fixing, welding, combinationsthereof, among others, with efficacy, as needed or desired.

The toroid drive 136 and the drive shaft 140 are rotatable about asubstantially central rotation axis 232. The toroid drive 136 has agenerally circular or curvilinear cam portion 234 and a generallycentral shank portion 236. As discussed further below, the cam 234 has aspecially designed generally circular or curvilinear outer rim 150 witha varying or non-uniform thickness.

The cam 234 and/or the outer rim 150 have a substantially central sideview plane 238. The cam 234 and/or the outer rim 150 are tilted relativeto a vertical plane or axis 240 by a predetermined angle α and hence tothe rotation axis by an angle β where β=90°−α. Thus, typically β and αare less than 90°.

In one embodiment, α is about 20° and β is about 70°. In anotherembodiment, α is in the range from about 10° to about 40° and β is inthe range from about 50° to about 80°, including all values andsub-ranges therebetween. In yet another embodiment, α is in the rangefrom about 5° to about 80° and β is in the range from about 10° to about85°, including all values and sub-ranges therebetween. In modifiedembodiments, α and β may be lower or higher, as needed or desired.

As schematically illustrated in FIG. 29, in one embodiment, the cam 234and/or the outer rim 150 are designed to provide a variable thicknessfor the outer rim 150 by the partial superimposition of two toruses ortoroids 242, 244 of substantially uniform rim thickness with respectivecentral axes 246, 248. By controlling the degree of superposition, therim 150 of variable and controlled thickness is created. Thus, thetransmission or power conversion system 98 is also referred to as a“hybrid dual or twin toroid” system.

Advantageously, the outer rim 150 thickness is varied such that the rim150 substantially continuously contacts the bearing surfaces 164 and 166as the cam 234 rotates about the central axis 232. Thus, desirably thetwo surfaces 164 and 166 can remain at a substantially fixed distanceapart as they move linearly back and forth in reciprocating motion inresponse to the cam's rotation about the central axis 232.

In the illustrated embodiment, the torus central axes 246, 248 are at anoffset angle θ to produce the desired variable thickness rim 150. Theslightly dimpled or grooved surface 250 is indicative of the partialsuperposition of the two toruses or toroids 242, 244. In modifiedembodiments, more than two toruses and/or toruses with variable rimthickness may be utilized to create the desired outer rim profile.

Advantageously, the dual torus or toroid (one toroid partially insideanother) configuration provides an elegant solution of for maintaining auniform distance between the bearing surfaces 164, 166 or drivenrollers. The rotation of the toroid or torus cam 234 moves the outer rim150 in a reciprocating motion with the motion being generally parallelto the rotary axis 232. The reciprocating motion of the slide plate 138is also generally parallel to the rotary axis 232 which is thentransmitted to the blade 106.

FIG. 30 shows the thickness profile of the outer rim 150 in accordancewith one embodiment. The thickness varies across the rim 150 in agenerally offset sinusoidal profile with a minimum thickness T_(min) anda maximum thickness T_(max). In modified embodiments, other suitable rimthickness profiles may be efficaciously utilized, as needed or desired.

The disposable cutting blade assembly 18 includes the integratedtransmission system 98 within the distal cover 72. The transmissionsystem 98 converts the rotary motion of the drive motor 80 into thereciprocating motion of the tissue-cutting blade 106. The transmissionsystem 98 is a sterile assembly of the disposable cutting blade assembly18 that is sterile packaged.

The transmission system 98 is an internal mechanism and is generallyhoused within the housing 96. This is important in that the “one timeuse disposable” tip assembly 18 embodiments because easy separation fromthe re-sterilizable motor drive portion of the powered handpiece 20. Intheses embodiments, the powered handpiece 20 with its rotary motor 80comprises an independent assembly from the disposable distal cutting tipassembly 18. Numerous sizes and shapes of distal cutting tip portion 92are available to be connected onto the motor drive powered handpiece 20.

Since the disposable distal cutting tip assembly 18 has an internalmechanism to convert rotary motion into reciprocating motion, itadvantageously enables a simple and cost effective means ofdisconnecting the two assemblies 18 and 20. The drive shaft 140 at itsproximal end 253 includes a female receptor hole 254 that is configuredto substantially irrotationally mate with a matching male distal shaftdrive protruding out of the motor drive 80.

FIG. 31A shows a simple female triangular hole 254 a in the drive shaft140 that can engage a triangular shaped distal shaft drive protrudingout of the motor drive assembly. When the distal tip assembly 18 and thepowered handpiece 20 are connected both the female triangular receptorhole 254 a and the motor's male triangular drive shaft can rotate intandem. The male and female features are free to mesh and align duringthe axial motion of connecting the disposable cutting tip assembly 18onto the reusable sterilizable motor handpiece 20.

A triangular shaped male mating drive is desirable because itfacilitates sterilization of the male triangular shaft. The surfacesthat are steam sterilized and reused are desirably simple surfaces thatare easy to wash and clean. The surfaces should also enable reliablecleaning prior to sterilization. A triangular male shaft has three flatsurfaces that are both easy to see and clean.

In modified embodiments, other suitable male-female mating drivepolygonal or non-polygonal interlocking configurations may be utilizedwith efficacy, as needed or desired. For example, FIG. 31B shows agenerally square or rectangular female receptor hole 254 b and FIG. 31Cshows a generally hexagonal female receptor hole 254 c.

FIGS. 32 and 33 show the cutting blade 106 and the drive slide 138. Theouter rim 150 of the toroid drive 136 engages the slide slot 156 andabuts against the bearing surfaces 164, 166 as it rotates toreciprocatingly displace the slide 138 connected to the blade 106. Theslide 138 can be generally above the toroid drive 136 or it can begenerally below the toroid drive 136. In modified embodiments, the slide138 can be to the sides of the toroid drive 136 as long as the outer rim150 rotates within the slide slot 156 and causes the slide to move in areciprocating motion.

It is important that the distal filing blade 106 maintain its structuralrigidity and not to fail in a buckling mode that would cause the fileblade 106 to become bent or distorted into a shape that may result in anundesirable thicker profile. To safeguard against this, in oneembodiment, a safety shear system is provided.

The slide 138 includes a pair of posts or pins 260, 262 that engagerespective blade holes 256, 258. In one embodiment, the posts 260, 262are formed from a molding process in which the slide 138 including theposts 260, 262 comprises a plastic. The posts 260, 262 in one embodimentare heat staked and the like to mushroom and form respective heads 264,266 to affix the blade 106 and the slide 138. The mushroomed pins 260,262 prevent undesirable blade buckling by being configured to shear at aforce much lower than the force that could potentially buckle the fileblade 106.

Thus, advantageously, the file blade 106 is driven by a structure thathas an intentional weak point that will shear away the drivingreciprocating action of the blade drive 106 to prevent a potentialdistal blade 106 buckling. The configuration of the shear pins 260, 262is tailored to the specific file blade configuration (which varies inwidth and length and cross sectional curve). Thus, the shear pinconnection including the diameter and/or cross-section of the mushroomedheads 264, 266 and/or the shank portions of the pins 260, 262 isconfigured such that the mushroomed pins 260, 262 shear at a force lowerthan a force that would buckle the specific distal cutting blade 106 andallow safe disengagement and disconnection of the blade 106 from theslide 138.

Advantageously, the diameter(s) of the pins 260, 262 provides adesirable shear pin safety mechanism. The pins 260, 262 allow theconnection between the drive slide 138 and the blade 106 to shear at apredetermined force. This force can be determined for a particularcutting blade configuration by a number of methods including modeling,numerical analysis, computer simulation, experimental and empiricaltesting and the like, among others. Accordingly, each differing cuttingblade 106 is provided with a shear connection feature to shear and stopthe blade driving action before the blade could conceivably buckle. Aclearance space 268 in the slide 138 is provided in the proximaldirection behind a blade proximal end 270 to allow the blade 106 to moveproximally in the slide part 138 when shear disconnection occurs so thatthe blade 106 is substantially decoupled from the reciprocating motion.

The safety shear force F_(shear) can be calculated as a function of theblade buckling force F_(buckle) in a number of ways to provide suitableprotection. In one embodiment, the shear force F_(shear) is about ⅓^(rd)of the blade buckle force F_(buckle). In another embodiment, the shearforce F_(shear) is in the range from about 0.25F_(buckle) to about0.75F_(buckle), including all values and sub-ranges therebetween. In yetanother embodiment, the shear force F_(shear) is in the range from about0.1F_(buckle) to about 0.9F_(buckle), including all values andsub-ranges therebetween. In modified embodiments, the shear forceF_(shear) may be lower or higher, as needed or desired.

FIGS. 32 and 33 illustrate a connection between the blade 106 and theslide plate 138 in accordance with an embodiment that provides a safetyshear decoupling between the 106 and the slide plate 138. In modifiedembodiments, as the skilled artisan will appreciate, the blade 106 andthe slide 138 may be connected utilizing other suitable techniques, asneeded or desired.

FIG. 34 shows the hybrid dual toroid drive 136 with a pair of associatedbearings 272, 274 operatively mounted on the slide plate 138. Thebearings 272, 274 and their toroid abutting surfaces 276, 278 are spacedby a predetermined distance that allows the variable thickness cam outerrim 150 to be in substantially continuous contact while rotating. Inthis embodiment, the rotation axis 232 is substantially perpendicular toa plane 280 between the bearing surfaces 276, 278.

The specially configured bearing abutting surfaces 282, 284 of the outerrim 150 advantageously provide an increased surface contact area withrespective bearing surfaces 276, 278. This desirably decreases thepressure load between driving toroidal surfaces 282, 284 and the drivenlinear slide follower bearings 272, 274 and their respective surfaces276, 278. The bearings 272, 274 also provide for a low friction contactwith the driving toroidal surfaces 282, 284 and advantageously improvewear-resistant properties.

FIG. 35 shows a modified embodiment wherein the toroid drive 136 has anouter rim 150 a that substantially contacts the bearing surfaces 276,278 mounted on the slide 138 in a low surface area or point contactarrangement. In further embodiments, the cam outer rim 150 can directlycontact the slide bearing surfaces 164 and 166, as needed or desired.

FIG. 36 shows the operation of the toroidal transmission and powerconverter system 98 in a laboratory system set-up. Rotation of thetoroid drive 136 is about the central rotary axis 232 is converted intolinear reciprocating motion of the slide 138 as generally indicated byarrows 204. The slide is connected to the cutting blade 106. Also shownare the slide bearings 272 and 274.

Irrigation Pump System

A pulsatile water pump system 290 is incorporated into the disposablecutting blade assembly 18 and is housed within the distal cover 72. Thepulsating water pump 290 supplies sterile water into a patient and inone embodiment is disposed after one use to insure no “patient topatient” bio-contamination. The pulsatile pump system of embodiments ofthe invention has utility in a number of fields and applications wherefluid transport is desired. In one embodiment, a pulse of water isprovided after each linear motion stroke.

The integrated cutting blade water pump system 290 is advantageouslydriven by blade motion and insures that the blade 106 will automaticallybe cooled and lubricated whenever the cutting blade 106 is inreciprocating motion. In modified embodiments, an external pump systemmay be utilized, as needed or desired.

The water pump system 290 lubricates the reciprocating blade movingparts. The water pump system 290 cools the reciprocating blade movingparts. The water pump system 290 provides clear water for optical visioncapability.

The pulsating water pump system 290 more effectively clears debris fromthe cutting blade surface for better cutting performance by providingpulsed jets of irrigation fluid. The pulsatile water pump system 290 isdriven by reciprocating cutting blade motion pumps water wheneverreciprocating blade 106 is driven. In modified embodiments, the systemmay have a manual override feature for pump operation.

FIG. 37 shows the pulsatile dual direction water pump system 290 inaccordance with an embodiment. The pump system 290 has a stationary pumpbody 292 that includes an inlet 294, a flow chamber 296 and an outlet298. The inlet 294 is fed water from the umbilical cord 16 or throughanother feedline. The outlet 298 provides water to the bearing retainer118 within the blade shield 108. The general direction of flow or thefluid path through the pump 290 is generally indicated by arrows 302.

The inlet 294 has a one-way or check valve 304 and the outlet 298 has aone-way or check valve 306 to prevent undesired back-flow. Any one of anumber of suitable valves may be used such as, but not limited to,pressure relief valves, ball-spring devices and the like.

The pump system 290 includes a pair of spaced spring-biased or -loadedplungers 308, 312. In modified embodiments, other suitable resilientbiasing or loading mechanisms may be efficaciously utilized, as neededor desired. The plungers 308, 312 can move back and forth into the pumpchamber 296 to selectively occlude the pump chamber 296 and/or fluidpath 302 to displace fluid and pulsatingly pump it to the desired site.Water is drawn in from the inlet 294 through the valve 304 as theplungers 308, 312 move back towards their undepressed position.

The slide 138 has a lower surface 314 with a pair of specially contouredand spaced cam surfaces 316, 318 that operatively couple the slide 138with the pump plungers 308, 312. During a forward linear stroke motionthe distal cam surface 316 contacts or abuts the distal plunger 308 anddepresses it to pump water out of the outlet 298. During a backwardlinear stroke motion the proximal cam surface 318 contacts or abuts theproximal plunger 312 and depresses it to pump water out of the outlet298.

Thus, the reciprocating linear stroke blade drive motion moves camsurfaces 316, 318 to alternatingly depress pump plungers and therebypump water in a pulsing modality whenever the driven cutting blade 106is moved through a linear stroke by the transmission system 98.Desirably, the transmission system 98 provides the motion, force orenergy to substantially simultaneously and synchronously drive thereciprocating blade 106 and the pulsatile pump system 290.

In embodiments of the invention, the water pump 290 is integrated intothe reciprocating blade mechanism. The pulsatile (pulsating with eachlinear stroke) water pump feature pulses a jet of water out through thecutting blade irrigation holes 212 to keep the cutting surface 114 cleanfor optimum cutting action. The pulse powered pump 290 is powered by thereciprocating action of the cutting blade 106. Advantageously, thisdirect drive eliminates a separate pump drive source. This desirablysaves parts and cost by eliminating a separate water pump.

The disposable cutting tip assembly 18 is sterile. It incorporates thewater pump 290 which is also sterile. The pump 290 is very close orproximate to the site where the pressurized water is provided.Advantageously, this reduces pressure losses that would be incurred ifthe pump is at a distance from the point of use. It desirably alsosolves the problem of sterilizing a far away water pump.

When the reciprocating blade device 106 is cutting it should be providedlubrication and cooling and the cutting surface 114 should desirablyalso remain clean and clear of tissue debris. The water pump 290 pumpswater when the cutting surface 114 is activated as the same drivemechanism drives both. Thus, an operator need not remember to activatethe pump 290 since its operation is automatically actuated with cuttingblade 106. Desirably, this provides a safety feature to prevent damage,galling, a freeze up and also prevents cutting debris buildup andthermal glazing.

The pump system 290 can be formed from a number of suitably durablematerials. In one embodiment, the pump system 290 is formed from asuitable plastic. The plastic material may comprise a suitablethermoplastic. In modified embodiments, other suitable plastics, metals,alloys, ceramics, combinations thereof, among others, may beefficaciously utilized, as needed or desired. Suitable surface coatingsor finishes may be applied, as required or desired.

The pump system 290 can be fabricated by using a number of manufacturingtechniques. These include, but are not limited to, molding, machining,casting, forging, laser cutting and/or processing, laminating,adhesively fixing, welding, combinations thereof, among others, withefficacy, as needed or desired.

FIG. 38 shows a pulsatile single direction eater pump system 290 a inaccordance with another embodiment. The pump system 290 a includes aplunger 320 connected to the slide 138. During forward linear strokemotion the plunger 320 occludes the pump cavity 296 to displace waterform the outlet 298 to the desired site. During backward linear strokemotion the plunger 320 moves in an outward direction from the pumpcavity 296 and water is drawn into the cavity 296 through the inlet 294.

Powered Handpiece

FIG. 39 shows the powered handpiece 20 including the cover or housing74, the video camera 78, the motor assembly 80 and a distal interfacemember 322 for connecting to the interface member 102 and coupling 104of the distal tip assembly 18. The interface member 322 has an opening324 substantially aligned with the interface opening 158 which allowpassage of the fiber optic probes 124, 126 for connection to the camera78.

The proximal end 70 of the distal tip assembly 18 and the handpiece'sdistal end or portion 326 are configured and adapted to provide a quickand reliable connection or mating. This includes, but is not limited to,mechanical docking, electrical docking, optical docking and hydraulicdocking

The housing 74 and motor assembly 80 are steam sterilizable. The steamsterilization process involves the application of hot water and steamunder pressure to kill germs followed by a partial drying process. Thedrying process is not always fully complete in that the instruments andparts processed, often come back partially wet. Usually there are smallpockets of standing water trapped in small pools created by part shapeswith water-titer pockets that end up facing upward due to thereplacement in the holding trays used to contain the parts and instrumentsto be steam sterilized.

With the routine use of steam sterilization it is desirable that anyoptical or electronic parts that are used with the steam sterilizedinstruments be designed to provide solutions to residual water and theproblems it can create with electro-mechanical and opto-mechanicalcomponents. As discussed further below, the motor housing also housesthe video camera module, which in inserted into the freshly sterilizedmotor housing. The hermetically sealed video camera module is designedto specifically address the specialized problems of residual water in afreshly steam sterilized surgical instrument in a sterile surgical setupenvironment.

The handpiece housing 74 has a motor housing 328 that receives the motorassembly 80 and the video housing 76 that receives the video camera 78.The video camera 78 is contained in the video housing 76 which providesa hermetically sealed housing. The video housing 76 desirably provides awater and gas sealed environmentally protective housing. The videocamera 78 optically connects to the proximal end 70 of the distal tipassembly 18 and interfaces with the imaging fiberoptics.

The cable 16, the cover 68 and the components of the handpiece 20 aresterilizable except for the video camera 78 that is hard to sterilize.During assembly in a sterile field operating room, the non-sterile videocamera 78 is inserted into a freshly sterilized handpiece housing 74. Ahermetic (gas and liquid) seal is created by O-ring seals or the like.The O-rings are part of the interface at the handpiece's proximal end330 and the distal end interface 322. Advantageously, this hardware andprocedure combined together enables a non-sterile delicate electronicvideo camera to be made bacteriologically safe inside the sterile outerhousing 74 of the sterilized handpiece 20.

The housing 74 also contains an LED illuminator 332 that connects to theillumination fiberoptics of the distal tip assembly 18. The LED (LightEmitting Diode) 332 is also mounted into the video housing 74 in awaterproof and gas-tight method to prevent intrusion and damage fromwater or water vapor accumulation. In one embodiment, a distal videoimaging lens 334 is recessed to help prevent accidental damage.

The camera 78 can be provided in a mount 336 with an outer shape that isdesigned to prevent the incorrect insertion into the housing 74. Themount 336 has a male structure 338 that is received within a matingfemale receptor opening 340 within the housing 74. The male structure338 provides the mount 336 with an asymmetrical cross sectional shapethat is intended to create a visually obvious shape that can be readilyinserted into its mating female receptor opening 340 in the correct ordesired orientation.

In one embodiment, the camera 78 and the mount 336 comprise a videomodule 342 with the camera 78 housed in a waterproof and air-tightmanner as discussed above in connection with the video housing 74. Thehermetically sealed video module 342 can then be fitted within in thehousing 74. The LED 332 can also be hermetically sealed within themodule 342, for example, in an opening 344.

The camera 78 can comprise any one of a number of suitable video ordigital devices. In one embodiment, the video camera 78 comprises adevice as available from Toshiba. Advantageously, the integration of thevideo camera 78 within the handpiece 20 greatly enhances the capability,compactness, utility and versatility of the system.

As discussed above, the sterilizable powered handpiece 20 contains anon-sterile non-sterilizable video camera 78 contained inside thesterile hand piece assembly. Advantageously, the sterile poweredhandpiece 20 hermetically seals the non-sterile video camera 78 in asterile housing 74 or 336, which permits safely using the sealedassembly in the sterile field and inside a patients body.

The handpiece 20 can include one or more switches or buttons that allowsthe user to operably control the surgical file operation. Alternatively,or in addition, the controls can be provided on a separate platformand/or on the control system 14.

The precision motor 80 can comprise any one of a number of suitablerotary motion creating devices such as, but not limited to, gas turbinesand electric motors and the like. In one embodiment, the motor 80comprises a gas or air turbine rotary motor that is fed pressurized airor gas through the umbilical cord 16.

In one embodiment, the gas turbine motor 80 is provided air or gas atabout 80 psi to run the device. In another embodiment, air or gas isprovided at a pressure in the range from about 50 psi to about 100 psi,including all values and sub-ranges therebetween. In modifiedembodiments, the pressure can be lower or higher, as needed or desired.

The motor assembly 80 at its distal end or portion 342 includes arotatable power shaft 344 connected to a rotatable drive shaft 346. Themotor distal end 342 docks with the proximal end 70 of the distal tipassembly 18. The power shaft 344 is generally received in the distal tipassembly holes 162, 160 and 149.

The motor 80 powers the reciprocating blade 106. The male drive shaft346 is substantially irrotationally received within the matching femalereceptor hole of the drive shaft 140 to provide rotary motion to thetransmission system 98 that converts it into linear reciprocatingmotion.

FIG. 40A shows a simple triangular shaft 346 a that can engage thetriangular receptor hole 254 a. When the distal tip assembly 18 and thepowered handpiece 20 are connected both the female triangular receptorhole 254 a and the motor's male triangular drive shaft 346 a can rotatein tandem. The male and female features are free to mesh and alignduring the axial motion of connecting the disposable cutting tipassembly 18 onto the reusable sterilizable motor handpiece 20. Thisdocking feature has a simplified rotary triangular shaped drive shaft,even though it drives a reciprocating (push-pull) motion-cutting blade.

A triangular shaped male mating drive 346 a is desirable because itfacilitates sterilization of the male triangular shaft 346 a. Thesurfaces that are steam sterilized and reused are desirably simplesurfaces that are easy to wash and clean. The surfaces should alsoenable reliable cleaning prior to sterilization. The triangular maleshaft 346 a has three flat surfaces that are both easy to see and clean.

In modified embodiments, other suitable male-female mating drivepolygonal or non-polygonal interlocking configurations may be utilizedwith efficacy, as needed or desired. For example, FIG. 40B shows agenerally square or rectangular male shaft 346 b and FIG. 31C shows agenerally hexagonal male shaft 346 c.

Surgical Methods

The methods which are described and illustrated herein are not limitedto the sequence of acts described, nor are they necessarily limited tothe practice of all of the acts set forth. Other sequences of acts, orless than all of the acts, or simultaneous occurrence of the acts, maybe utilized in practicing embodiments of the invention.

The surgical instrument of embodiments of the invention enable theremoval of obstructions in the tubular spaces (neuroforamen) between thevertebras of the neck and back. Desirably, this allows surgeons tonavigate into the tiny (neuroforamen) canals between delicate nerveroots and remove small amounts of bony overgrowth (osteophytes) underdirect vision.

Embodiments of the invention allow a surgeon to safely navigate downinto the neuroforamen canal next to the nerve roots and see and removeobstructions that cause nerve compression with direct vision. Thesurgeons can perform a new surgical procedure, a “micro foramentomy”through as small as about a ½ inch to about 1 inch incision. Thisadvantageously represents a truly minimally invasive surgical procedurewhich would serve to benefit patients and surgeons.

FIGS. 41 and 42 show a bone and/or tissue cutting procedure using thesurgical instrument 12. The shielded cutting blade 106 is inserted intoa neuroforamen 348 between a vertebra 350, unwanted bone and/or tissue352 and a nerve root 354. The shield 108 protects the nerve root 354while the blade cutting surface 114 removes the bone and/or tissue 354to relieve nerve compression by enlarging the neuroforamen 348.

Advantageously, embodiments of the invention provide a high level ofcutting blade control and enable surgeons to reach into previouslyinaccessible areas to remove unwanted bone with precision, sensitivityand complete safety and confidence. The shielded cross sectional profileof embodiments of the cutting tip permit protection of delicate nervesduring the neuroforamen enlargement process to relieve nervecompression.

As seen in FIG. 42, the shielded portion 108 of the file is facing thedelicate nerve 354 and the opposite cutting surface 114 is facing thebone that is to be removed 352 to enlargen the bony and cartilagestructural opening. Advantageously, the surgical instrument ofembodiments of the invention has a cutting surface 114 that can travelaround corners. A direct vision system allows surgeons to safelynavigate into blind cavities of the patient's body and also assistsvisualization of the actual tissue cutting action and its results.

In the embodiments of a sterile disposable (one time use) cutting tipassembly 18, the cutting tip assembly 18 is used typically, in oneembodiment, for about three minutes in a two-hour surgical procedure.The tip of the distal assembly 18 can provide the surgeon with a pictureof the area, and enable the doctor to see the cavity and its anatomicalfeatures.

The view is magnified so the user sees a full screen image of the smalltunnel, which is typically, in one embodiment, about one quarter of aninch in diameter. The enlarged view of the area allows surgeons toinspect and find the exact location and size of nerve irritation andcompression, and determine where and how much bone and cartilage toremove to eliminate the nerve compression and relieve the pain.

Orthopaedic File Embodiment

FIGS. 43-45 show different views of an orthopaedic shieldedreciprocating surgical file instrument or apparatus 12 a. The surgicalfile instrument 12 a generally comprises a distal tip assembly 18 adocked to and powered by a handpiece 20 a.

The distal blade assembly 18 a generally comprises a reciprocating blade106 a with a cutting surface 114 a and a shield or guard 108 a. Thecutting surface 114 has an abrasive material or abrasives 206 a.

The distal blade assembly 18 a further includes a handle 356 above theblade 106 a. The handle 356 is used by a surgeon to press against ordown on the bone and/or tissue material to be removed. The handle 356 isshaped to facilitate manipulation and has a suitable ergonomic shape orthe like. The handle 356 further includes an opening 358 to facilitateoperation.

From the foregoing description, it will be appreciated that a novelapproach for precision bone and/or tissue removal surgery has beendisclosed. While the components, techniques and aspects of the inventionhave been described with a certain degree of particularity, it ismanifest that many changes may be made in the specific designs,constructions and methodology herein above described without departingfrom the spirit and scope of this disclosure.

Various modifications and applications of the invention may occur tothose who are skilled in the art, without departing from the true spiritor scope of the invention. It should be understood that the invention isnot limited to the embodiments set forth herein for purposes ofexemplification, but is to be defined only by a fair reading of theappended claims, including the full range of equivalency to which eachelement thereof is entitled.

1. A modular surgical instrument comprising: a rotary drive operable tooutput rotary motion; a transmission coupled to the rotary drive, thetransmission including an input portion and an output portion, thetransmission being operable to convert rotary motion at the inputportion to linear reciprocating motion at the output portion; a bladecoupled to the output portion of the transmission in linearlyreciprocating relationship, the blade including a shaft extending from afirst end to an opposite second end, the second end including cuttingelements, the second end reciprocating in response to reciprocation ofthe output portion; a blade housing enclosing the blade first end andshaft such that all of the moving parts of the blade are enclosed exceptfor the second end.
 2. The modular surgical instrument of claim 1wherein the transmission is releasably engageable with the rotary drive.3. The modular surgical instrument of claim 2 further comprising a fluidpath between the second end of the blade and a reservoir.
 4. The modularsurgical instrument of claim 1 further comprising a sliding drive membercoupled to the output portion of the transmission and interposed betweenthe output portion of the transmission and the second end of the blade,the drive member comprising a polymer and the second end of the bladecomprising a metal.
 5. The modular surgical instrument of claim 1wherein the output portion of the transmission is enclosed in atransmission housing, the transmission housing having a dimensiontransverse to the direction of linear reciprocating motion of the outputportion and the blade housing having a dimension transverse to thedirection of linear reciprocating motion of the first end of the blade,the transmission housing mating with the blade housing, the bladehousing being narrower near the second end of the blade than near thefirst end of the blade.
 6. The modular surgical instrument of claim 5wherein the blade housing transitions from a generally curved profilenear the blade first end to a generally flat profile near the bladesecond end.
 7. A method of performing a spinal decompression comprising:providing a powered surgical instrument having a handle, a linearreciprocating blade having cutting elements operable to remove tissue ata surgical site, and a blade housing enclosing the blade, the bladehousing having an opening for exposing the cutting elements; positioningthe blade so that the cutting elements abut tissue that is impinging ona spinal nerve; actuating the blade so that it linearly reciprocates thecutting elements relative to the impinging tissue to remove theimpinging tissue.
 8. The method of claim 7 wherein the blade housing hasa first side and an opposite second side, an opening being formed in thefirst side for exposing the cutting elements and the second side forminga tissue shield, the method further comprising positioning the bladehousing with the first side toward impinging tissue and the second sidetoward the nerve to shield the nerve from the blade.
 9. The method ofclaim 7 further comprising holding the blade housing stationary relativeto the surgical site while the blade reciprocates relative to thesurgical site.
 10. The method of claim 7 further comprising deliveringfluid to the blade.
 11. The method of claim 7 wherein the blade andblade housing have a proximal end nearer the handle and a distal endnearer the cutting elements and the blade and blade housing are bentnear the distal end to allow cutting around a corner, the method furthercomprising positioning the blade at the opening of a natural cavity, theopening forming a corner, to remove impinging tissue around the corner.12. The method of claim 12 wherein the natural cavity comprises a neuralforamen.
 13. The method of claim 12 wherein the blade housing isrelatively rigid and the blade is relatively flexible, the blade bendingto follow the bend in the blade housing as the blade reciprocates. 14.The method of claim 12 wherein the blade guide is narrower near thedistal end.
 15. The method of claim 12 wherein the powered surgicalinstrument includes an optical pathway allowing visualization of thedistal end of the blade, the method further comprising visualizing theimpinging tissue as it is removed by the reciprocating blade.
 16. Amethod of performing a spinal decompression comprising: providing apowered surgical instrument having a handle assembly comprising a driveoutput configured to output linearly reciprocating motion; a blade guidemounted to the handle assembly, the blade guide having a proximalportion having a proximal guide axis and a distal portion having adistal guide axis, the distal guide axis being oriented at an anglerelative to the proximal guide axis, a blade having a distal cuttingportion, the blade being mounted in the blade guide and coupled to thedrive output, the blade being constrained by the blade guide toreciprocate the distal end of the blade parallel to the distal guideaxis; positioning the distal cutting portion of the blade adjacenttissue that is impinging on a spinal nerve; actuating the blade toreciprocate the cutting portion against the impinging tissue to removethe impinging tissue.